Project Summary: Tufts University physics professor Allan Cormack pioneered the field of tomography. His seminal work, from 1963 and 1964, provided both the mathematical foundations of computerized tomography (CT), and tangible proof-of-concept by engineering a rudimentary CT scanner. Taken together, this effort represented the first practical method to see into an object without physically breaking it open. Along with the engineer Godfrey Hounsfield, he won the 1979 Nobel Prize in Physiology or Medicine for these contributions. Since then, tomography has broadened to include a wide range of modalities and problems. This field is unique for the rich interplay among applications in medicine, security, earth sciences, industry, physics, and the mathematics required to solve these problems. This international conference at Tufts, ?Modern Challenges in Imaging: In the Footsteps of Allan Cormack? will honor the achievements of Cormack and reflect this diversity in the field by gathering top international researchers in mathematics, engineering, science, and medicine to communicate the most current research and challenges in the field. This will include work on mathematical models of emerging modalities, tomographic machine learning, dynamic methods, and spectral imaging with applications include medicine and security. The best research from the conference will be disseminated in a special issue of the journal Inverse Problems. Talks will be posted on the conference website. The organizers will recruit a diverse set of experienced participants and trainees, and the conference will be advertised in a range of publications reflecting the scientific and demographic diversity of the field. This conference is unique in that it combines high-level mathematical participants with experts in medical and industrial CT. It is structured to encourage participants from different fields to talk with each other, broaden their horizons, and make connections between problems and methodologies in the various fields. Several of the plenary talks will provide introductions to the areas. Trainees will be integrated into the conference through an informal welcome lunch and a poster session to introduce them to researchers in the field. This supports goals 1, 4, and 5, of the NIBIB: Researchers will present innovative biomedical technologies, engineering solutions, and mathematical methods to better image the body and objects more generally. The synergy between research areas will support the translation of technologies from the academic sphere to medical utility. The training opportunities for graduate students and beginners support the training of the next generation of diverse scientists.